Machine for dressing external cylindrical surfaces



NVENTOQS finson f v MTTO@| Eye 5 Sheets-Sheet 1 A. M. JOHNSON ET ALFiled Feb. 23, 1958 MACHINE FOR DRESSING EXTERNAL CYLINDRICAL SURFACESJune 27, 1939.

June'27, 1939. A. M. JOHNSON ET AL 2,164,067

MACHINE FOR DRESSING EXTERNAL CYLINDRICA SURFACES Filed Feb. 25, 1938 5Sheets-Sheet 2 June 27, 1939. A. M. JOHNSON ET AL 2,164,067

MACHINE FOR DRESSING EXTERNAL CYLINDRICAL SURFACES Filed Feb. 23, 1958 5Sheets-Sheet 3 iNVENTOQS June 27, 1939. A. M. JoHNsoN ET AL 2,164,067

MACHINE FOR DRESSING EXTERNAL CYLINDRICAL SURFACES Fil ed Feb. 23, 19385 h t 4 Patented June 27, 1939 UNITED STATES PATENT OFFICE MACHINE FORDRESSING EXTERNAL CYLINDRIC'AL SURFACES Application February 23, 1938,Serial No. 191,912

18 Claims.

The invention relates to machines for dressing cylindrical surfaces, andmore particularly to a machine for producing a true contour and smoothfinish on the external surfaces of shafts and other elongatedcylindrical bodies.

I-Ieretofore, the finishing of such cylindrical bodies has beenaccomplished generally by a grinding operation. This operation isordinarily performed with an abrasive wheel revolving on a fixed axiseccentric of the work, the wheel having merely tangential contact withthe surface of the work piece and therefore in operative engagement witha relatively small area thereof. The operation results in appreciableroughness and irregularity in the finished surface as well as inobjectionable variations in the diameter and concentricity of the workat different points along its length. The latter defect is particularlynoticeable in the case of substantially elongated bodies such as shafts,tubes, pistons, etc.

The present invention aims to overcome the defects inherent in thefinishing operations heretofore employed and to this end is embodied ina machine for accurately and smoothly dressing the external surfaces ofelongated cylindrical bodies by a honing or lapping operation in whichthe surface to be dressed is acted on by abrasive stones having aconstant contact therewith over a substantial area. The abrasive stonesare conveniently arranged in a'circular series in an annular frameencircling the work piece and are urged radially of the frame intoconstant engagement with the surface of the work piece. Relativereciprocation between the tool and the Work, together with eitherconstant or intermittent rotation of one relative to the other, isutilized to rub the abrasive stones over the entire surface of the workpiece to hone or lap the sur face to the desired finished condition.

With the foregoing in view, one object of the invention is to provide amachine adapted to effect relative rotational and reciprocato-ry motionbetween an elongated cylindrical work piece and a tool of the characterabove described, ina manner such that the tool is caused to actuniformly over the entire surface area to be dressed and to quickly trueand smooth the surface.

, Another object is to provide an improved machine for dressing externalcylindrical surfaces which may be adjusted to handle work pieces ofwidely varying length.

Another object is to provide an improved reciprocatory carriage formachines of the above general character which is of relatively lightlimit the invention to the specific form disclosed weight and yetextremely rigid and which may be manufactured economically.-

Still another object is to provide improved means for operativelyconnecting a rotatable member on a reciprocatory carriage with a sta- 5tionarily supported power-actuated driving means.

A further object is to provide improved control devices for machines ofthe above general character.

Other objects and advantages of the invention will become apparent fromthe following detailed description of the preferred embodimentillustrated in the accompanying drawings, in which Figure 1 is a planview of a machine embodying the features of the invention.

Fig. 2 is a side elevation of the machine.

Fig. 3 is a side elevation of the reciprocatory carriage with theheadstock and other appurtenances removed.

Fig. 4 is a plan view of the carriage shown in Fig. 3.

Fig. 5 is a transverse sectional view of the carriage taken along theline 55 of Fig. 4.

Fig. 6 is a transverse sectional view of the carriage taken along theline 66 of Fig. 4.

Fig. '7 is a view partly in section of the means provided for supportingthe drive shaft on the carriage.

Fig. 8 is a fragmentary side view of the carriage showing the drivinghead or headstock in elevation with a portion broken away to show thearrangement of the driving gear train.

Fig. 9 is an end elevation of the carriage and headstock.

Fig. 10 is a side elevation of the intermediate support for the limitswitch supporting rod, as viewed from one end of the machine.

Fig. 11 is a side elevation of the support shown in Fig. 10.

Fig. 12 is a fragmentary end view of the tool and tool supportingfixture.

Fig. 13 is a sectional view taken along the line Iii-l3 of Fig. 2showing details of the short stroking mechanism.

Fig. 14 is a detail View of the short stroking mechanism taken along theline 14-! of Fig. 13.

Fig. 15 is a schematic diagram of the electrical and hydraulic circuitsof the machine.

While the invention is susceptible of various modifications andalternative constructions, we have shown in the drawings and will hereindescribe in detail a preferred embodiment, but it is to be understoodthat we do not thereby intend to but intend to cover all modificationsand alternative constructions falling within the spirit and scope of theinvention as expressed in the appended claims.

Referring to Figs. 1 and 2 of the drawings, the machine selected toillustrate the invention comprises generally an elongated horizontallydisposed base !6 having on its upper face a track or guideway comprisingspaced parallel guide bars I! (Fig. 9). A head or carriage i8 issupported on the guideway for movement longitudinally of the base M3 byadjustable spool-shaped roller bearings l9 (Figs. 6 and 9) mounted onopposite sides of the carriage for engagement with the guide bars H. Thecarriage l8, as herein shown, is equipped with a headstock 2B and atailstock 2! having centers 22 and 23, respectively, between which awork piece 24 may be supported in operative relation with a relativelystationary external honing tool 25.

While the tool 25 may be of any suitable construction, one of the mostsuitable for dressing external cylindrical surfaces comprises acylindrical body 26 within which a plurality of abrasive stones 2! (Fig.12) are arranged in a circular series. The stones are mounted formovement radially of the body 25 and suitable adjusting means actuatedby knurled nuts 28 are provided for moving them radially inwardly toengage the surface of the work piece which extends concentricallythrough the tool.

In the particular machine disclosed, the tool 25 is supported on astationary fixture 28 adjustably mounted on the base I6 of the machine.The adjustable mounting of the support permits shifting the tool towardor from the head end of the machine so that it may be positioned at anypoint required for proper operation on work pieces of different lengths.

The fixture 28 may be of any suitable construction and, as herein shown,comprises a transverse member 29 extending across the base l6 above thecarriage l8. Projecting upwardly and forwardly from the member 29 is anarm 30 which, with the member, provides spaced supports for the tool 25.The arm 30 is formed with a slot opening toward the front of the machinewhile member 29 has a similar slot opening toward the end of themachine, the slots being formed to receive lugs 3| and 32 formed on aplate 33 rigid with the body 26 of the tool. The slot in arm 33 may beleft open as the rotation of the Work tends to rock the tool in aclockwise direction as viewed in Fig. 12, and thus preventsdisengagement of the lug. The slot in the member 25!, however, isprovided with a latch or keeper 34 which holds the lug in place andserves to prevent endwise movement of the tool incident to thereciprocation of the work piece. The slots are preferably ofsufiiciently greater size than the lugs to permit limited lateralmovement or floating, of the tool to enable the tool to properly centeritself on the work piece. Axial and rotational movement of the tool iseffectively prevented by the supporting fixture.

Means is provided for reciprocating the carriage l8 and for rotating orindexing the work piece 24 to efiect the desired relative movement between the tool and the work piece. As shown in Figs. 1 and 2, the meansfor reciprocating the carriage comprises a cable drum 35 supported atone end of the machine and arranged to be driven in either direction bya rotary fluid motor 36 which receives pressure fluid from a suitablepump 31 driven by an electric motor 38. The cable drum is operativelyconnected with the carriage by means of flexible cables 39 and 40 whichare secured to the drum so that one cable is Wound up and the other paidout incident to the rotation of the drum. The cable 40 passes over asheave 4| at the end of the machine opposite the drum so that the forcewhich it exerts on the carriage is opposite in direction to the forceexerted by the cable 39. Thus, the carriage is moved to the left ortoward the foot of the machine upon rotation of the cable drum in acounterclockwise direction as viewed in Fig. 2. Rotation of the drum inthe opposite direction returns the carriage toward the head of themachine. With this arrangement, the carriage is reciprooated with aminimum of shock incident to the changes in direction of movement.

The direction of rotation of the cable drum 35 and, hence, the directionof movement of the carriage I8 is controlled by a reversing valve 42interposed in the hydraulic circuit of the fluid pressure motor 36 asshown in Fig. 15. The reversing valve has a shiftable valve plunger 43operative in one position to direct pressure fluid to the motor toeffect rotation of the drum in a clockwise direction and effective inthe other position to reverse the rotation of the drum. Pressure fluidsupplied by a high pressure pump 44 driven by the pump motor 38 isutilized for shifting the valve plunger under control of asolenoidactuated pilot valve 45 the operation of which will be describedin more detail hereinafter.

Means is provided for delaying operation of the reversing valve 42 forthe purpose of introducing a dwell in the reciprocation of the carriageto increase the period of engagement between the tool and an area of thework piece adjacent a shoulder or other obstruction. To this end, thehydraulic circuit for the valve is provided with an adjustable delayedaction valve 46 arranged to control the rate of fluid discharge. In theparticular embodiment disclosed, only one delayed action valve isemployed, thus providing a dwell at one end of the reciprocatory stroke.It will be appreciated, however, that a second valve may be incorporatedin the reversing valve circuit when it is-desired to provide a dwell atboth ends of the reciprocating stroke.

When operating on a shouldered work piece, accurate control of carriagemovement is essential to enable the tool to work up to the shoulder andyet avoid contact between the same which might damage the tool. Toobtain such control, the machine is provided with an adjustable stop inthe form of a cross bar 46 slidably supported on the base I6 formovement toward and from the rear end of the carriage 18 as shown inFigs. 1 and 2. The face of the cross bar carries pads or bumpers 41 ofrubber or other suitable resilient material spaced longitudinally of thebar for engagement by stop-engaging members 48 on the end of thecarriage. The members 48 may be screw threaded in suitable supportingblocks 48 welded or otherwise secured to the carriage so that they maybe adjusted independently to insure simultaneous engagement with thebumpers 4?. Clamping screws 49 serve to hold the cross bar in setposition on the base so that the carriage is stopped by engagement ofthe members 48 with the bumpers 41 before the shoulder of the work piecehits the tool.

The means for rotating and indexing the work comprises suitablepower-driven means mounted on the base 16 and operatively connected withthe headstock 20 by means of a splined drive shaft 50. The power-drivenmeans may be generally similar to that disclosed in the patent to AlbertM. Johnson, No. 2,106,217, granted January 25, 1938, and includesgenerally an electric motor 5| for rotating the shaft 50 continuouslyand a hydraulic cylinder 52 and piston 53 for indexing the shaft. Aswill be seen by reference to Fig. 15, the cylinder 52 is connected inthe hydraulic circuit of the carriage reciprocating motor 36 so that thepiston is shifted to opposite ends of the cylinder alternately each timethe motor is reversed. The piston is formed with rack teeth meshing witha gear 54 arranged to drive the shaft 50 through a pawl and ratchetmechanism such as that disclosed in the aforementioned patent. Throughthe medium of a clutch (not shown) operable under control of a manuallever 55, either the motor 5| or the hydraulic mechanism above describedmay be connected selectively with the splined driveshaft 56 to rotate orindex the shaft.

The drive shaft 56 is journaled on the base l6 at its driven end only,and means is provided on the carriage I 8 for supporting the oppositeend of the shaft. This makes it unnecessary to extend the shaft for theentire length of the base as has heretofore been the practice,eliminates any possibility of the shaft binding when the carriage isadjusted on the guideway by taking up play between the rollers l9 andthe guide bars I1, and additionally provides a substantially longerbearing surface which minimizes wear and eliminates vibration. Tothis'end, the shaft is arranged to telescope into a tubular member 56supported at opposite ends on the underside of the carriage l8. As shownin Fig. '7, the end of the member 56 adjacent the foot of the machine isfitted with a plug 51 which has a stud 58 projecting beyond the end ofthe member. The stud is journaled in a roller bearing 59 supported by abracket 66 depending from the carriage l8. The other end of the member56 is anchored to a flange 6| formed integrally with a gear 62 supportedin antifriction bearings 63 in a depending portion of the headstock, asshown in Fig. 8. The tubular member 56 preferably has an internaldiameter such as to receive the shaft snugly, thereby permittingrelative axial sliding movement of the parts and yet serving tosupportthe shaft in a manner such that vibration is substantially eliminated.The gear 62, above referred to, has a slidable nonrotatable relationwith the 7 drive shaft 50 so that the gear and tubular member 56 rotatewith the shaft and wear on the interior of the member is reduced to aminimum.

Gear 62 is utilized to drive a hollow spindle 64 journalled on theheadstock 20, which spindle is adapted to receive the center 22. In thepresent instance, the drive for the spindle is taken through anintermediate gear 65 meshing with a gear 66 rigid with the spindle.Rotational movement of the spindle may be imparted to the Work by asuitable dog 61, as shown in Fig. 1. It will be apparent that with theconstruction above described the work piece 24 may be rotated or indexedand simultaneously reciprocated relative to the tool 25. Accordingly,the tool is enabled to act uniformly on the entire surface area of thework piece and to dress it to a true contour and smooth finish.

Means is provided for supplying an ample flow of clean coolant fluid tothe work during the honing process to remove loose particles of metal orabrasive and to prevent undue heating of the.

tool or work. The coolant supply means includes a suitable pump 68 (Fig.15) driven by an electric motor 69. As shown in Fig. 1, the pump andmotor are mounted at one side of the base I6 adjacent the rear end ofthe machine. The pump is arranged to draw the coolant from a reservoir70 preferably located within the base l6 and to deliver the coolantunder pressure to a suitable filter ll. After passing through thefilter, the coolant is carried to the work by a pipe 12 which terminatesin branches l3 and 14 positioned to direct the coolant over the work atopposite ends of the tool 25.

In order to reduce the weight of the reciprocating parts to a minimum,the invention contemplates the use of a carriage of novel and improvedconstruction which is light in weight and yet extremely rigid. Referringto Figs. 3 to 6, the carriage in its preferred form is fabricated fromsheet or plate stock with the various elements welded together to form aunitary structure.

As herein shown, the carriage I 8 comprises generally an upperrectangular box-like frame having side walls 15, end walls 16 and abottom plate ll. The bottom plate is. slotted longitudinally as at 18throughout a substantial portion of its length, and below this slot ismounted a trough-like lower frame having side walls 19, end walls 80,and a bottom plate 6|.

Within the lower frame are fitted a plurality of longitudinally spacedtransverse stiffening members 82 in the form of inverted, generally U-shaped plates. These are welded to the side walls and the bottom plateof the frame, thus forming a series of compartments or pockets in whichcoolant draining from the work piece may be collected. Each of thepockets is provided with an outlet 63 in one of the side walls fordraining the coolant into a trough for return to the coolant reservoir'56. As shown in Figs. 5 and 6, the bottom wall SI of the lower frame isinclined slightly in the direction of the opening 83 to facilitate thedischarge of the coolant.

The stiffening members serve to render the lower frame of the carriagevery rigid and additional rigidity is obtained by the provision oftriangular gusset plates 84 extending between the side walls 79 of thelower frame and the underside of the bottom plate ll of the upper frame.These plates, together with the stiffening members 82, give the carriagetransverse rigidity, while the vertical side Walls of the upper andlower frames render the carriage rigid longitudinally.

Welded to the side and bottom walls of the upper frame at spaced pointsalong the lateral edges of the carriage is a series of blocks 85 havingvertically disposed bores adapted to receive supporting studs 86 whichcarry the spool-shaped bearing members l9 for supporting the carriage onthe guide bars ll. In the particular embodiment shown, eight of theroller bearings are employed, four on each side of the carriage,although it will be appreciated that this number may vary with carriagesof different lengths.

Formed integrally with the upper and lower frames at the forward end ofthe carriage is an extension 86 constituting a base to which theheadstock 26 may be bolted. A bed plate 8? extending longitudinally ofthe upper frame and secured to the bottom plate 11 as by bolts 88provides a support for the tailstock 2|. In order to adapt the machinefor handling work pieces of diiferent lengths, adjustment of thedistance between the centers 22 and 23 is essential. Accordingly, thetailstock is adjustably mounted on the bed plate 81 by means of asuitable clamp engaging a T-slot 89 extending longitudinally of the bedplate. With this arrangement, the machine may be readily adapted to holda work piece of any length within the capacity of the machine.

Suitable control means is provided for controlling the power-drivenmeans for rotating the work and reciprocating the carriage. This meansincludes manually operable devices for starting and stopping the variousmotors together with limit switches actuated by the carriage in itsmovement to control the direction of carriage movement. As shown inFigs. 1 and 2, two limit switches are provided, one switch 9! definingone end of the carriage stroke and another switch 92 defining the otherend of the stroke. These switches may be of any suitable and well knownconstruction. and include an operating member 93 adapted to be engagedby a dog 94 mounted on the carriage, as shown in Fig. 10. When the dogengages the operating member, the associated switch is closed tocomplete a circuit for one of the solenoids 95 and 98 which actuate thepilot valve 45 to control the supply of pressure fluid to the drivingmotor 36 for the cable drum 35.

In order to adjust the movements of the carriage to conform to thelength of the work piece being dressed, means is provided for varyingthe relative spacing of the limit switches as required. To this end, theswitches are mounted on a rod 91 extending longitudinally of the baseit. The arrangement is such that either switch may be moved along therod to any desired position and a set screw 98 firmly clamps the switchin set position.

The limit switch rod 97 is supported at opposite ends by brackets 98mounted on the base i6. Suitable means is provided for supporting therod intermediate its ends in a manner such that the adjustment of thelimit switches is not interfered with. As shown in Figs. 10 and 11, thesupporting means includes a post 99 slidably supported below the rod formovement toward and from the same in a bracket 509 carried on the sidewall of the base 56. A pin iEiI projecting radially from the postthrough a vertically disposed slot I02 on the brackets H30 provides ahandle by wh ch the post may be moved to its upper position to engageand support the rod 9?. The post is normally held in its upper positionby a detent in the form of a flat bar I93 pivoted at one end on thebracket I09 and adapted to engage in a slot in the side'of the post. Aspring H34 actng on the bar holds it in latching position. When it isdesired to move one of the limit switches past the supporting post, thelatch I03 is withdrawn, thereby permitting the post to drop into itslower position and out of the path of the limit switch.

It may be necessary at times to position a limit switch substantially atthe point at which the support is located. In order to avoid anydifficulty on this score, the bracket E is slidably supported on adovetailed slideway I05 for movement longitudinally of the base. Aclamping screw I06 serves to hold the bracket in set position on theslideway.

In some cases, it is desirable to subject specific areas of the workpiece to additional action of the tool to remove high spots orirregularities. For this purpose. manually operable means is providedfor controlling the reciprocatory movements of the carriageindependently of the carriage-actuated limit switches above described.This operation is commonly known as short stroking.

The manual control or short stroking mechanism comprises a pair ofswitches I0! and I08 connected in parallel with the limit switches 9|and 92 in the circuits of the pilot valve solenoids and 96, as shown inFig. 15. Referring to Fig. 14, the switches I01 and I08 are mounted inopposed relation in a casing I09 mounted in a conveniently accessibleposition on the front wall of the base I6. Operation of the switches iseffected selectively through the medium of a hand lever I I0 fast on arock shaft I I I journaled in the casing I09. Mounted on the rock shaftIII within the casing is a collar IIZ having a radially projecting lugII3 engageable with one end of a switch operating member IE4 which ispivoted on the casing I09 at its other end.

The switch operating member H4 is disposed between the switches I01 andI08 and engageable therewith to close the switches alternately whenrocked about its pivot by means of the hand lever IIO. Thus, when thehand lever is rocked in a clockwise direction as viewed in Fig. 14, thelug II 3 rocks the switch-actuating member in a counterclockwisedirection to close the switch I0'I. On continued movement of the handlever, the lug is moved out of the path of the switchactuating memberand the member is returned to normal by the spring action of the switch.Closure of the switch I08 is efiected by rocking the hand lever in theopposite direction. The lug H3 and switch-actuating member H0 thusconstitute a load and fire mechanism which permits the switches to beopened and closed in rapid succession. This action imparts a series ofquick, short reciprocatory strokes to the carriage I0. It will beapparent that the short stroking may take place at any point along thepath of the carriage travel so that any selected area on the work piecemay be subject to additional action of the tool.

The electrical and hydraulic circuits of the machine as hereindisclosed, are shown diagrammatically in Fig. 15 of the drawings.Referring to the drawing, it will be observed that the various drivingmotors, including the coolant pump motor 69, the spindle driving motor5% and the pressure fluid pump motor 38, are all arranged to be startedand stopped under control of push button switches convenientlyaccessible to the operator. The coolant motor 69, for example, isstarted in operation by momentary actuation of a push button switch H5which complpetes a circuit from a conductor IIG of the power line,winding of a solenoid II l, starting switch II5 and a normally closedstop switch E I6 to the other conductor I 59 of the line. The solenoidII! on energizing operates a switch I29 to close the operating circuitfor the motor 69. At the same time, the solenoid completes a holdingcircuit for itself by closing switch i2I. Operation of the push buttonswitch IIB opens the holding circuit for the solenoid, which thereuponbecomes deenergized and opens the circuit for the motor 69.

The spindle driving motor 5| is provided with starting switches I22 andI23 arranged to connect the motor with the line circuit for operation ineither direction. Switch I22 is actuated by a solenoid I24 and switchI23 is operated by a solenoid I25 which are connected in circuitselectively by a manually operable reversing switch I26. A normally openpush button starting switch I 21 and a normally closed push button stopswitch I20 are connected in circuit so as to control either solenoidconnected up by the reversing switch. With the reversing switch in thetime.

position shown in the drawings, closure 'of the switch I21 completes anenergizing circuit for the solenoid I24 extending from line conductor I5, winding of solenoid I 24, reversing switch I26, starting switch I21and stop switch I28 to line conductor II9. Solenoid I24 closes the motorswitch I22 and completes a holding circuit foritself independently ofthe starting switch by way of its own holding switch I29 and a normallyclosed auxiliary switch I30 which shunts the starting switch. .With thereversing switch in its other position, solenoid I25 is energized uponthe closure of starting switch I21 to close the motor switch I23 andcomplete a holding circuit for itself by way of switch HI and auxiliaryOpening of the stop switch I 28 is switch I30. effective to deenergizeeither solenoid and stop the motor The circuit for the pump motor 38includes a switch I32 arranged to be closed by a. solenoid I33 energizedby momentary actuation of a push button starting switch I34; Thesolenoid by closing a switch I35 completes a holding circuit for itselfby way of a normally closed auxiliary switch I36 and a normally closedpush button stop switch I31. Momentary opening of the stop switch I31 iseffective to stop the pump motor and thus discontinue the supply ofpressure fluid to the hydraulic carriage reciprocating motor,

carriage. 7

Auxiliary switches I30 and I36 are operated by a solenoid I38 forautomatically stoppingthe machine under control of a stroke counter ortimer. The counter or timer may be of any suitable type and is providedwith a normally open switch I39 closed either in response to theoperation of the carriage through a predetermined number ofreciprocations or after a predetermined intervalof circuit for thesolenoid I38 which opens the auxiliary switches I30 and I36 and thusstops the spindle driving motor and hydraulic pump motor. f

When it is desired to stop the machine before the operation of theswitch I39, this may be" done by operating a push button switchI40'which completes a circuit for the solenoid I38 independently of theswitch I39. The switch I39'may be rendered inefiective temporarily tostop the machine when it is desired to increase the number of strokes orto increase the operating period by opening a normally closed switch I4|which is connected in series relation with the switch I39.

It will be observed that the circuit for the solenoid I38 is completedthrough limit switch 9| which is closed when the carriage is at theextreme right or head end of the machine. Thus, automatic stopping willinvariably take place with the carriage in retracted position.

Limit switches 9| and 92 and the multiply connected short strokingswitches I01 and I08 are arranged respectively to control circuits forthe draulic motor 36 which accordingly moves the carriage toward theright.

Having in mind the foregoing detailed descrip+ The switch I39 completesan energizing" tion of the preferred embodiment of the invention, theoperation of the machine will be read ily understood. In operating themachine, the first step of course is to set up the work between thecenters 22 and 23. This is most conveniently done by first inserting thework piece through the tool and then adjusting the tailstock so that thecenters engage the ends of the work piece in the usual manner. The toolis then secured to the tool supporting fixture by engagingthe lugs 32 inthe slots provided for this purpose in the fixture.

The carriage stroke is adjusted by setting the limit stops 9| and 92 onthe control rod. These switches are positioned so that the dog 94engages the respective switches as the ends of the work piece approachthe tool. The stroke counter or timer may also be set to close theswitch I39 when the work piece has received the required number of tooloperations.

If the work is to be honed, the clutch-actuating lever 55 is set toconnect the spindle driving motor 5| with the splined drive shaft 50.The driving motor 5|, pressure fluid pump motor 38 and coolant pumpmotor 69 are started by operation of the appropriate push buttonswitches.

The honing operation then proceeds without further attention untiluninterrupted by the closure of the counter or timer switch I39 whichstops the drive motor 5| and pump motor 38 upon the carriage reachingthe end of its return stroke.

For the lapping operation, the clutch control lever 55 is shifted tooperatively connect the hydraulic indexing mechanism of the drive shaft50. The machine is then started exactly as in the previous instance,except that the spindle drive motor 5| remains idle. Stopping themachine is effected automatically by the counter -.or timer through themedium of the switch I39.

A shaft may also be polished by reciprocating it relative to the toolwithout either rotation or indexing. In this case, therefore, the clutchlever is set in the position to connect the spindle driving motor 5|with the drive shaft 50. The motor, however, is not operated; henceneither the drive shaft nor the work is rotated. Reciprocation of thecarriage is effected in the usual way to effect relative movement of thetool and work in a straight line. I

It will be apparent from the foregoing that the invention provides amachine of novel and improved construction for dressing externalcylindrical surfaces to a true contour and smooth finish. The machine isadapted to effect relative rotational and reciprocatory motion betweenan elongated cylindrical work piece and an external honing tool in amanner such that the tool is caused to act uniformly over the entiresurface area to be dressed, thereby removing all high spots andirregularities and producing an extremely smooth accurate surfacefinish. The machine may be readily adjusted to handle work pieces ofwidely varying lengths.

The invention also provides a reciprocatory machine tool carriage ofnovel and advantageous construction. The carriage is fabricated fromsheet or plate stock which reduces the weight to a minimum withoutsacrifice of rigidity. Due to the light weight of the carriage, it maybe reciprocated at relatively high speeds without placing undue strainon the framework or driving mechanisms. Further reduction in the weightof reciprocating parts is obtained by the provision of novel means foroperatively connecting a rotatable member on the reciprocating carriagesupporting fixture mounted on said base, a cylindrical abrasive toolsupported by said fixture, a headstock and a tailstock on said carriagehaving centers for supporting a work piece concentrically of said tooland with its axis parallel tothe reciprocating path of the carriage,means for reciprocating said carriage to traverse the work past thetool, a motor mounted on said base, and means operatively connectingsaid 'motor with the headstock center for rotating the work piece duringthe reciprocation of said carriage, said connecting means including asplined shaft driv ingly connected with said motor and extendingsubstantially parallel to the reciprocatory path of the carriage, and atrain of gears carried by said carriage for movement therewith, one ofsaid gears being rigid with the headstock center and another of saidgears having a slidable nonrotatable relation with said shaft.

2. In a machine for dressing external cylindrical surfaces, incombination, an elongatedhorizontally disposed base, a carriagesupported for reciprocation longitudinally of the base, a'toolsupporting fixture mounted 'onsaid. base,'a cylindrical abrasive toolsupported by said" fixture, a headstock and a tailstock on said"carriage for supporting a Work piece concentrically of said tool andwith its axis parallel to thereciproca'ting path of the carriage, saidheadstock havinga spindle drivingly connected withthe work piece,

means for reciprocating said carriage to traverse the work past thetool, a splined shaft 'journaled at one end on said base underlyingthecarriage and extending substantially parallel-to its reciprocatory path,a train of gears supported on said carriage for movement therewith,oneof said gears being rigid withtne headstock spindle and' another of saidgears having a slidable' nonro tatable relation'with said shaft;and'meansfor" driving said shaft to rotate the'work piece relative tosaid tool.

3. In a machine for'dressing external cylindrical surfaces, incombination, an elongatedhorizontally disposed base, a carriagesupported for reciprocationlongitudinally of the base, a tool supportingfixture mounted on said base, a. cylindrical abrasive tool supported bysaid fixture, a

headstock and a tailstock on said'carriage for supporting a work piececoncentrically of'said' tool and with its axis parallel to thereciprocating path of the carriage, said headstock having a rotatablespindle drivingly connected with the work piece, means for reciprocatingsaid carriage to traverse the work past the-tool, a splined shaftjournaled at one end on said base underlying the carriage and extendingsubstantially parallel to its reciprocatory path, a train of gearssupported on said carriage for movement therewith, one of said gearsbeing rigid with the headstock spindle and another of said gears havinga slidable non- .rotatable relation with said shaft, first poweractuatedmeans operative to drive said shaft for imparting continuousrotation tothe work piece, a second power-actuated means operative to drive saidshaft intermittently to index the work piece, and manually operablemeans for rendering said power-actuated means effective selectively.

4. In a machine for dressing external cylindrical surfaces, incombination, an elongated horizontally disposed base, a carriagesupported for reciprocation longitudinally of the base, a toolsupporting fixture mounted on said base, a cylindrical abrasive toolsupported by said fixture, a headstock and a tailstock on said carriagefor supporting a work piece concentrically of said tool and with itsaxis parallel to the reciprocating path of the carriage, said headstockhaving a spindle for rotating the work piece, means for reciprocatingsaid carriage to traverse the work past the tool, a splinedshaftjournaled at one end on said base underlying the carriage and extendingsubstantially to its reciprocatory path, a rotatable member on saidcarriage supporting the other end of said shaft, a train of gearssupported on said carriage and movable therewith, one of said gearsbeing rigid with the headstock spindle and another of said gears beingrigid with said rotatable member and having a slidable nonrotatablerelation with said shaft, and a motor on the base'for driving said shaftto rotate the work piece relative to said tool.

5. In a honing machine, in combination, an elongated base, a carriagemounted for reciprocation on said base, a rotatable element on saidcarriage, means for rotating said element including a motor mounted onsaid base, a splined shaft drivingly connected with said motor andextending substantially parallel to the reciprocatory path of thecarriage, a stationary bearing on said base supporting one end of saidshaft, means for supporting the other end of said shaft on saidcarriage, said' supporting means comprising a tubular member adapted toreceive the shaft in telescoping relation, means rotatably supportingsaid member on the carriage, and means on the carriage drivinglyconnecting said shaft with'said rotatable element.

6. In a honing machine, in combination, an elongated base, a carriagemounted for reciprocation on said base, a rotatable element on saidcarriage, means for rotating said element including a motor mounted onsaid base; a splined shaft drivingly connected with said motor andextending substantially parallel to the reciprocatory path of thecarriage, a stationary bearing on said base supporting one end of saidshaft, means providing a bearing for the other end of said shaftcomprising a tubular member rotatably supported on said carriage andadapted to receive the shaft in telescoping relation, said member havinga sliding nonrotatable relation with the shaft, and a train of gears fordrivingly connecting said shaft with said rotatable element including agear rigid with the rotatable element and another gear rigid with saidtubular member.

7. In a honing machine, in combination, an elongated base, a carriagemounted for reciprocation on said base, a rotatable element on saidcarriage, means for rotating said element including a motor mounted onsaid base, a splined shaft drivingly connected with said motor andextending substantially parallel to the reciprocatory path of thecarriage, a stationary bearing on said base supporting one end of saidshaft, means providing a bearing for the other end of said shaftcomprising an elongated tubular member adapted to receive the shaft intelescoping relation, and antifriction bearings rotatably supportingsaid member at spaced points on said carriage.

8. In a machine of the character described, in combination, areciprocatory carriage comprising, a rectangular upper box-like framefabricated from flat plates, said frame having side walls, end walls anda bottom wall, a slot in said bottom wall extending longitudinallythereof for a substantial portion of its length, a lower frame alsofabricated from flat plates having side walls, end walls and a bottomwall, said lower frame being of substantially the same width as saidslot and disposed in registration therewith, transverse stiffeningmembers interposed between the side walls of said lower frame, andoutwardly projecting gusset plates extending between the side walls ofsaid lower frame and the bottom wall of said upper frame, all of saidparts being welded together to form a rigid structure of relativelylight weight.

9. In a machine for effecting rapid reciprocation between a honing tooland the cylindrical surface of a work piece, in combination, a supportfor the tool, a support for the work piece, and a reciprocatory carriagefor one of said supports comprising, a rectangular upper box-like framefabricated from flat plates, said frame having side walls, end walls anda bottom wall, a slot in said bottom wall extending longitudinallythereof for a substantial portion of its length, a lower frame alsofabricated from flat plates having side walls, end walls and a bottomwall, said lower frame being of substantially the same width as saidslot and disposed in registration therewith, inverted generally U-shapedstiffening members interposed between the side walls of the lower frame,and gusset plates extending between the side walls of the lower frameand the bottom wall of the upper frame, all of said parts being weldedtogether to form a rigid structure of relatively light weight.

10. In a machine for dressing the cylindrical surface of a work piecewherein the work piece is rapidly reciprocated relative to astationarily supported honing tool, the combination of a reciprocatorycarriage for suporting the work comprising, a rectangular upper box-likeframe fabricated from flat plates, said frame having side walls, endwalls and a bottom wall, a slot in said bottom wall extendinglongitudinally thereof for a substantial portion of its length, a lowerframe also fabricated from flat plates having side walls, end walls anda bottom wall, said lower frame being of substantially the same width assaid slot and disposed in registration therewith, transverse stiffeningmembers interposed between the side walls of said lower frame, outwardlyprojecting gusset plates extending between the side walls of said lowerframe and the bottom wall of said upper frame, all of said parts beingwelded together to form a rigid structure of relatively light weight, anextension formed integrally with said frames at one end of the carriage,a headstock supported on said extension, a bed plate mounted over saidslot and removably secured to the bottom wall of said upper frame, and atailstock adjustably supported on said bed plate for movement toward andfrom said headstock.

11. In a machine for dressing the cylindrical surface of a work piece bya rapid reciprocation of the work piece relative to the tool, thecombination of a reciprocatory carriage for supporting the work piececomprising, a rectangular upper box-like frame fabricated from fiatplates, said frame having side walls, end walls and a bottom wall, aslot in said bottom wall extending longitudinally thereof for asubstantial portion of its length, a lower frame also fabricated fromflat plates having side walls, end walls and a bottom wall, said lowerframe being of substantially the same width as said slot and disposed inregistration therewith, inverted generally U-shaped stiffening membersinterposed between the side walls of the lower frame, all of said partsbeing welded together to form a rigid light-weight structure, saidstiffening members being spaced apart longitudinally of the lower frameto form therewith a series of upwardly opening pockets for the receptionof liquid coolant, and slots in one side wall of the lower frameproviding outlets for said pockets.

12. In a honing machine of the type in which the work piece is rapidlyreciprocated relative to a honing tool, the combination, of areciprocatory carriage for the work piece comprising, a rectangularupper box-like frame fabricated from fiat plates, said frame having sidewalls, end walls of the lower frame and the bottomwall of theupperframe, all of said parts being welded together to form a rigid.light-weight structure, and bearing supporting brackets disposed withinsaid upper frame at spaced points along the side walls thereof, saidbrackets being welded to the side and bottom walls of the frame toconstitute integral units of the structure.

13. In a machine for dressing cylindrical surfaces, in combination, anelongated base, guide bars extending longitudinally of the base, acarriage supported for reciprocation on said guide bars, a cylindricalabrasive tool stationarily supported on said base and disposed above thereciprocatory path of said carriage, means on the carriage forsupporting a cylindrical work piece in operative relation to sa d tooland with its axis substantially parallel to the reciprocatory path ofthe carriage, means for rotating the work piece, pressure fluid-actuatedmeans for imparting continuous reciprocatory motion to said carriage totraverse the rotating work piece past sa d tool, valve means controllingsaid pressure fluid actuated means to limit the range of movement ofsaid carriage, electrically operated means for actuating said valvemeans, and means for controlling said electrically operated meansincluding a pair of limit switches supported on said base for operativeengagement by said carriage at the extreme limits of its movement, saidswitches being adjustable relative to each other to vary the range ofcarriage movement.

14. In a machine for dressing cylindrical surfaces, in combination, anelongated base, guide bars extending longitudinally of the base, acarriage supported for reciprocation on said guide bars, a cylindricalabrasive tool stationarily supported on said base and disposed above thereciprocatory path of said carriage, means on the carriage forsupporting a cylindrical work piece in operative relation to said tooland with its axis substantially parallel to the reciprocatory path ofthe carriage, means for rotating the work piece, pressure fluid-actuatedmeans for imparting continuous reciprocatory motion to said carriage totraverse the rotating work piece past said tool, valve means controllingsaid pressure fluidactuated means to limit the range of movement of saidcarriage, electrically operated means for actuating said valve means,automatic means for controlling said electrically operated meansincluding a pair of limit switches supported on said base for operativeengagement by said carriage at the extreme limits of its movement, andmeans for controlling said electrically operated means independently ofsaid limit switches comprising a second pair of switches, and manuallyoperable means for operating said last mentioned switches selectively.

15. In a honing machine, in combination, an elongated horizontallydisposed base, a carriage supported for reciprocation longitudinally ofsaid base, power-actuated means for reciprocating said carriage, a rodextending longitudinally of said base and supported at opposite ends onthe side walls of the base, limit switches for controlling saidpower-actuated means adjustably supported on said rod for engagement bysaid carriage at the extreme limits of its movement, and means forsupporting said rod at an intermediate point including a member mountedon said base, said member being retractible to permit movement of eitherlimit switch past said intermediate point.

16. In a honing machine, in combination, an elongated horizontallydisposed base, a carriage supported for reciprocation longitudinally ofsaid base, power-actuated means for reciprocating said carriage, a rodextending longitudinally of said base and supported at opposite ends onthe side walls of the base, limit switches for controlling saidpower-actuated means adjustably supported on said rod for engagement bysaid carriage at the extreme limits of its movement, and means forsupporting said rod at an intermediate point including a member mountedon said base, said member being shiftable longitudinally of the rod topermit unrestricted adjustment of said limit switches.

17. In a honing machine, in combination, an elongated horizontallydisposed base, a carriage supported for reciprocation on said base,poweractuated means for imparting continuous reciprocating motion tosaid carriage, a member extending transversely across the base andadjustably secured thereto, resilient pads on said member, andadjustable elements on said carriage engageable with said pads topositively limit the movement of the carriage.

18. In a machine tool, in combination, a base, guide bars mounted onsaid base in parallel spaced relation to form a guideway, a carriageadjustably supported on said guideway for reciprocation thereon, arotatable element on said carriage, means for rotating said elementincluding a motor mounted on said base, a splined shaft drivinglyconnected with said motor and extending substantially parallel to thereciprocatory path of the carriage, and means for supporting said shaftso as to avoid any possibility of binding when the carriage is adjustedon the guideway comprising, a stationary bearing mounted on said basefor supporting one end of the shaft, and a bearing on said carriage andreciprocable therewith for supporting the other end of the shaft.

ALBERT M. JOHNSON. WALTER M. FAIRBAIRN.

